The game mechanic is really really fun in a minimalist way. But it can gets repetitive very soon. Please allow more varieties at the mid-game to late game. Perhaps introduce some new elements upon buying a new vehicle, in order to make progressing the game more rewarding?
Or when you buy some expensive vehicle it grants a universal bonus like coin multiplier to make grinding easier and progress quicker.
Having played realm grinder, I'd have to say this game is no where near that standard. What is attractive in this game is the map that shows an ever-expanding empire.
For those who think the first level is hard, here's a tip: build very few towers and upgrade them all to the max. I started with 3 towers and ended with 5 level 5/6 towers. And got a gold medal for it. Don't buy gems until you can get 200 gold pieces without waiting too long.
The graphics is nice. I hate that there is no indicator of where to go, and I really hate I have to walk to the edge of the screen to see a little bit of what's ahead. It'd be nice if I can see at least 2/5 of what is ahead instead of 1/8.
Nice song, lovely. Nice challenge too. You'll get it once you finish the game. The end game badge took a while to load, got me worried for half a minute.
Grinding to get the third ally can take less time if you keep killing the weaker enemies. Instead of killing the strongest enemy that gives 5 points to your alignment, find the enemy that gives you 4 points.